关键词: 北方地区, 土地利用, 沙漠化

Abstract: Land sandy desertification is one of the most serious environmental and so cial economic problems in Northern China.The processes of desertification mainly have being controlled by the interaction of human activities and fragile eco environment,which means the pattern and intension of landuse are major factors for development or reverse of desertification.Since the increase of human impact on landuse which had been forced by the increasing pressure of population,the farming pastoral transitional zone in Northern China has been moving towards north,resulting in changes in landuse structure from grazing to cropping to a large extent and destruction of natural vegetation cover.Consequently,wind erosion induced desertification process got accelerated.According to statistics of desertified land areas with different landuse purposes,human activities related sandy desertification were grouped as over cultivation(25%),over grassing(28%),excess firewood gathering(32%) and mis used water resources(8%).During the last 5 decades,sandy desertified land has expanded continually in Northern China,where total area has exceeded 350,000km2 by the mid 1990s.Based on remote sensing monitoring,we found that the growth rate of desertified land has being increased decade by decade,such as the annual average spread area had increased from 1,560km2 between the 1950s to the mid 1970s,to 2,100km2 between the mid 1970s to the late 1980s,to 2,460km2 in the last decade.But some successful models in combating desertification have proved that where the reasonable landuse practice has been adopted over certain years,the sandy desertified land has would get reversed and can be used again for more effective farming or graszing.

Key words: Northern China, landuse, sandy desertification